The back sticking was developed by a good friend of mine John Dowling may he rest in peace. He first introduced it to the drum and bugle Corps activity in the very early 60s, with the United States Air Force, drum quartet, taking first place. It is used by many bands and Drum Corps and Fife and Drum Corps, today.
Well, friend Marco, they’re the U.S. Army, not a reenactment group, and therefore have zero input in what their uniforms are; just like all other active duty soldiers.